The one big thing I'd really like to see change in MMOs is pulling strategy.
Be it in the open world or in an instance, it's all about the pull.
We try to clear out a room with as few mobs/NPCs per pull as possible. It's like the other enemies in the room or area simply doesn't realize that we're picking them off one by one.
In the open world, many players will run "out of aggro range" if they pull too many mobs/NPCs.
In level / class based games, it feels to me that the "balance" is made for one on one encounters will enemies. You're a level 50, so you should try and pull a single level 50 mob/NPC to fight.
Even in a group, we rely on mezzes and roots etc. too limit the number of creatures that we are fighting at once. Of course, this all goes back to the Holy Trinity of Tank/Damage/Heal. You incapacitate as many enemies as possible per pull so the Tank has less to manage and the Damage has more focus. The Damage keeps the enemies dead, the Tank keeps the hurt'n on him/herself, and the Healer keeps the Tank alive.
But how Heroic does that feel?
For one, it is totally unrealistic.
Mob A - "Hey look, Bill and Frank are fighting on the other side of the room! Should we help?"
Mob B - "No no no. We'll wait till they get closer and attack us first, or we just so happen to walk close enough to them before we attack."
But what do we see in movies? The Hero charges in and battles against dozens, if not hundreds of foes at once. Only when facing truly dangerous and powerful foes are the fights one on one in some grand, epic battle.
This should be the way MMORPGs are too. Make aggro based off of line of sight and audio detection, not some physical distance or range between the enemies and us.
Balance it so that characters can and should be taking on swarms of enemies at once, being truly heroic as they stand against an onslaught of foes.
And have Boss battles be the epic encounters that are the exception to this rule, where the Hero(s) face off against a powerful foe in Epic combat.
We've all had (I imagine) encounters in our favorite MMO dungeons where we have pulled way, way, way too many enemies towards us and barely come out alive. How exciting was that? To battle against a seemingly impossible number of foes and come out victorious?
Throw in realistic combat systems like terrain modifiers, collision detection, and more advance line of sight and you've got yourself the potential for truly epic combat.
Right now, in level based games, it's pretty much the exact same thing every time, just different levels. You pull and kill a single level 10 mob when you are level 10, and you pull and kill a single level 50 mob when you level 50. Why not make the number of enemies we can handle at once go up with our rising levels, rather then ONLY the level of the enemies we face?
I'd like to see MMORPGs that are built around that principle of design, rather then built around the "slow and safe" / "Holy trinity" approach.
What about you?